Technology has been developed that enables different images to be perceived from different directions on the same display screen by use of a liquid crystal display device and a parallax optical element such as a parallax barrier, which is a light blocking barrier, or a lenticular screen or the like (Patent References 1 and 2). Among the products that have been developed by use of this technology are dual view displays that can simultaneously display a navigation image to the driver's seat and a television image to the passenger's seat, and naked eye 3D displays that can present the left eye and right eye with images having a parallax offset without the use of special glasses.
A problem known as crosstalk, in which an image that should be presented in one direction is perceived superimposed on an image that should be presented in another direction, occurs in display devices such as the above.
Crosstalk is produced by various factors; one type of crosstalk is electrical crosstalk that arises because the electrical signal for one sub-pixel electrically affects adjacent sub-pixels. Patent Reference 3 discloses a technique for correcting such electrical crosstalk by providing LUTs (lookup tables) corresponding to the signal level of the sub-pixel to be corrected and the signal levels of adjacent sub-pixels and correcting the signal level of the sub-pixel to be corrected on the basis of the signal levels of the adjacent sub-pixels.
When a display device puts multiple images on the same display screen and displays them in different directions in order to display separately directed images or to display a 3D image, crosstalk may conceivably arise from a structure such as the parallax barrier, lenticular screen, or the like that is not present in an ordinary liquid crystal display device. One example is optical crosstalk that occurs when image light that should be presented in one direction leaks out in another direction. Patent Reference 4 discloses a technique for correcting such optical crosstalk by correcting the gradation level of a sub-pixel to be corrected according to the gradation levels of sub-pixels of the same color in adjacent pixels.
Liquid crystal displays also have the drawback of being unable to respond quickly enough to fast-changing moving pictures because when drive voltage is applied to a liquid crystal, a certain time is needed before the proper transmittance is attained. There are techniques for improving the response speed of a liquid crystal to solve this problem (Patent References 5 and 6). Patent Reference 5 discloses a method that compares the current image data and the image data one frame before, supplies the liquid crystal panel with a liquid crystal drive signal corresponding to an image data value greater than the present image data value when the current image data value is greater than the image data value one frame before, and supplies the liquid crystal panel with a liquid crystal drive signal corresponding to an image data value less than the present image data value when the current image data value is less than the image data value one frame before. Patent Reference 6 discloses a method that detects field-to-field level changes of respective pixels from the input image signal and the image signal one field before and adds these level changes to the input image signal.